According to 3 GPP (3rd Generation Partnership Project), which is a project aiming to standardize a mobile communication system, a technology for power saving (energy saving), which reduces the power consumption of a network, has been introduced (for example, see Non Patent Document 1). For example, a cell managed by a base station is set to an OFF state (Deactivate) in the nighttime etc. when communication traffic is less.
Furthermore, according to the 3 GPP, in Release 12 and later, an improved energy saving technology is proposed to be introduced. For example, when setting one cell to an OFF state, transmission power of a neighboring cell is caused to be increased. As a result, it is possible to extend a coverage of a neighboring cell such that the neighboring cell supplements a coverage of a cell that is set to an OFF state (hereinafter, called as “OFF target cell”).